Author
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Cahoon, Edgar |
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Submitted to: Plant Lipids International Symposium Proceedings
Publication Type: Proceedings Publication Acceptance Date: 6/15/2004 Publication Date: 11/16/2004 Citation: Cahoon, E.B. 2004. Metabolic engineering of vitamin e biosynthesis for tocotrienol production and increased antioxidant content. In: Proceedings of the 16th International Plant Lipid Symposium, June 1-4, 2004, Budapest, Hungary. p.25-28. Interpretive Summary: Technical Abstract: This proceedings article highlights our recent research that has uncovered the biochemical and genetic basis for the synthesis of tocotrienols in monocot seeds. Tocotrienols are the principal form of Vitamin E in the seed endosperm of cereal grains. As described in the article, cDNAs for homogentisate geranylgeranyl transferase (HGGT) were isolated from barley, wheat, and rice. This enzyme catalyzes the committed step in the tocotrienol biosynthetic pathway. Expression of this enzyme in model plant systems conferred tocotrienol biosynthetic ability and resulted in large increases in total Vitamin E content. Structural characterizations of monocot HGGTs revealed that these enzymes contain seven transmembrane helices and are phylogenetically related to UbiA prenyltransferases. Results from studies of model plant indicated that HGGTs have strong, but not exclusive, substrate specificity for geranylgeranyl diphosphate. |
